Terconazole (cis-1-[p[[2-(2,4-dichlorophenyl)-2-(1H-1,2,4-triazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy]phenyl]-4-isopropylpiperazine) (C26H31Cl2N5O3) is a drug which has been useful for treatment of vaginal yeast infections as a cream containing about 0.4 or 0.8 percent by weight terconazole.
Terconazole is substantially insoluble in water at neutral pH. Terconazole hydrochloride has a solubility of about 0.007 percent by weight in water at neutral pH. Because of this low solubility, it is difficult to obtain stable terconazole solutions in water at concentrations required for therapeutic effect.
There is a need for aqueous terconazole solutions that include at least about 0.4 percent by weight dissolved terconazole, and which are free from terconazole crystals. Such solutions are useful in the preparation of pharmaceutical products for the treatment of yeast infections. Viscous aqueous compositions are particularly desirable, because they provide rapid release of the terconazole and generate the relatively high terconazole concentrations required for rapid killing of pathogens. The present invention provides such aqueous terconazole compositions.